Examples of generic devices for ground compaction include attachable compactors, which can be connected, e.g., to a hydraulic arm of an excavator as an exchangeable tool or an attachable implement. Further examples of generic devices for ground compaction include compaction rollers such as single-drum rollers or tandem rollers, which can be driven by an operator from an operator platform, as well as hand-guided compaction rollers, with which the operator walks next to the compaction roller. Further generic hand-guided devices for ground compaction comprise vibrating tampers, also called vibratory rammers, and vibrating plates, also called vibratory plate compactors. Generic devices for ground compaction are frequently used in street and road construction, underground construction and in the construction of squares, etc., in order to increase the compaction of the ground and thus improve its load-bearing capacity. These generic devices typically include a frame and a drive motor supported by said frame. The drive motor can be, e.g., a combustion engine or, e.g. in the case of attachable compactors, can also be configured as a hydraulic motor. The drive motor usually drives a vibration exciter connected to a ground compaction apparatus. The ground compaction apparatus is in particular typically a base plate, e.g., in the case of attachable compactors, vibrating tampers or vibrating plates, or a roller drum, as typically provided in the case of self-propelled and hand-guided compaction rollers. The vibration exciter is typically designed to cause the ground compaction apparatus to vibrate at a fixed vibration frequency or within a vibration frequency range during a compaction operation in order to improve the compaction performance of the device for ground compaction. The vibrations are transferred from the ground compaction device to the ground to be compacted and further the compaction of the ground material.
It is known in the prior art to provide a conversion device for the conversion of vibrations into electrical energy on the ground compaction apparatus, said conversion device converting the vibrations of the device for ground compaction into electrical energy, which is in turn supplied to a consumer. Consumers frequently employed on ground compaction apparatus according to the prior art include in particular at least one sensor of a sensor arrangement and/or of a transmitting unit, which are designed, e.g., to ascertain the degree of compaction of the ground being traversed by the ground compaction apparatus and transmit it, e.g. via a transmitting unit, to a device for evaluating the data. The degree of compaction is typically ascertained as a ground stiffness, which increases with increasing compaction. It can thus be concluded from the attainment of a certain ground stiffness that a sufficient ground compaction has been reached. A possibility for determining the ground stiffness is disclosed, together with its mathematical basis, e.g., in EP 2 627 826 D1.
The advantage of using a conversion device to supply a consumer with electricity is that there is no need for the consumer to be supplied from an additional power source, e.g., in an onboard network of the device for ground compaction, via error-prone cable connections. Especially when the consumer is arranged on vibrating components of the device for ground compaction, reliable cable connections for the supply of the consumer are complex and expensive, which is why it is advantageous to obtain the necessary electric energy for the consumer independently of the remaining ground compaction device by means of the conversion device arranged near the consumer. The technique of obtaining electric energy from vibrations through a conversion device is known as energy harvesting. These systems are based, e.g., on electromagnetic induction or the piezoelectric effect. A disadvantage here is the fact that the combination of sensors for ascertaining the degree of compaction and conversion devices for the supply of power to the sensor is relatively expensive.